I have a 16GB one I am filling with Bing and Yahoo photos. When I plug it in the USB, the thumbnails have begun to not fully populate. Instead of the photo, its a illustration of a page with a red and yellow sailboat scene. Sometime the first half of the thumbnails are like this, sometimes the last half, and sometimes multiple sections inbetween. The thumbnails used to show up from beginning to end, so I could see the photo each one had. Any ideas how to return it to this?